WO1992000680A1

WO1992000680A1 - PROCESS FOR EVENING OUT THE pH VALUE OF FRESH MEAT

Info

Publication number: WO1992000680A1
Application number: PCT/EP1991/001238
Authority: WO
Inventors: René Aemig
Original assignee: Vesten Ag
Priority date: 1990-07-11
Filing date: 1991-07-03
Publication date: 1992-01-23
Also published as: AU8008991A; BR9105814A; KR920002034A; DE4022007C1; CA2065725A1; KR930012204B1; EP0491896A1

Abstract

A process is disclosed for evening out the pH value of fresh meat, in particular veal, pork, poultry, lamb and game. The meat of animals freshly slaughtered is cut in individual pieces of meat and layered without any free spaces in a container, then a pressure is exerted on the layered pieces of meat from the outside, so that an osmosis takes place within and between the layered pieces of meat, because of the inner pressure thus generated in an anaerobic storage state. The meat is stored for at least seven days at a cooling temperature between -1 C and about +2 C.

Description

Method for making the pH of

Fresh meat

The present invention relates to a method for equalizing the pH of fresh meat, in particular beef, pork, poultry, lamb and venison.

It is known that each muscle piece of an animal has a different pH value and that different pH values can even be present within a single muscle piece. So fluctuates e.g. the pH value between 5.3 and 5.8 for normal meat and between 5.8 and 6.2 for pork meat which is still considered tolerable. Since the pH value strongly influences the tenderness, the color, the taste and the water binding capacity and the shelf life of the fresh meat, its non-uniformity in the fresh meat leads to strong fluctuations in the meat quality.

The invention has for its object to develop a method by means of which the quality of the fresh meat can be improved with respect to the tenderness of the meat, the color, the taste and the water-binding capacity and the durability of the meat. According to the invention, a method for this purpose is used to even out the pH of fresh meat, in particular beef, pork and poultry meat, freshly slaughtered meat being divided into individual pieces of meat and layered in a container without a gap, and then applied to the layered pieces of meat from the outside pressure is generated such that an anaerobic storage state of the pieces of meat is achieved and osmosis takes place within the layered pieces of meat and between them due to the internal pressure generated, storage for at least seven days at a cooling temperature of between −1 ° C. and approx. + 2 ° C takes place. The invention is thus based on the knowledge that by generating a sufficient internal pressure in the meat while simultaneously creating an anaerobic atmosphere, ie by suppressing and excluding the entry of oxygen, osmotic processes are favored in such a way that a pH value Compensation can occur in the individual pieces of meat or muscle pieces and between the individually stored muscle pieces.

Such osmotic processes cannot be achieved with the known meat processing methods. For example, a method is known in which each individual piece of meat or muscle piece is packed in a plastic bag and this bag is then evacuated. In this case, there can be no exchange between the individual muscle pieces themselves and an otic exchange within the muscle piece is also not possible, since the existing internal pressure is insufficient for this. Rather, the osmosis effect is prevented precisely by the evacuation. Another method of fresh meat processing, especially with beef, is to leave the individual pieces of meat together in the grown state. However, it is not possible to compensate for the pH here, since the individual muscle pieces are covered by a skin fleece, and this skin fleece is impermeable and prevents osmosis. In addition, there is no sufficient internal pressure that could cause the osmotic effect within and between the muscle pieces. In addition, this method is not possible with pork and poultry meat because the bacterial infestation prevents a longer storage period. However, the method according to the invention prevents bacterial infection by creating an anaerobic atmosphere.

The effect of the method according to the invention is confirmed by the following comparative tests:

So-called beef lower shells were compared at a storage temperature of 1 ° C., which had been stored on the one hand by the method according to the invention and on the other hand in evacuated plastic bags by the known method. Lower shell lower shell

Vacuum invention pH values pH values

5.73 5.53 5.69 5.62 5.47 5.64 5.48 5.62 5.49 5.64 5.46 5.62 5.45 5.63

Hip pieces of beef were also examined, resulting in the following pH values:

Hip hip

Vacuum invention pH values pH values

5.68 5.71 5.66 5.78 5.73 5.76 5.68 5.75 5.65 5.70 5.51 5.71 5.67 5.65

The above individual pH values were measured at comparable locations of the individual pieces of meat along the length of the piece of meat.

As can be seen from the above comparative measurements, the invention achieves an equalization of the pH value, the effect of an additional Increasing the average pH value results in that the overall meat quality is evened out and in particular the tenderness of the meat is improved.

A further effect of the method according to the invention is that a high 0 ₂ partial pressure is generated thereby, which causes oxygen to attach to the divalent iron of myoglobin present in the meat via a secondary valence, thereby forming oxy-myoglobin which cherry-red coloring of the meat causes the appearance of the meat stored according to the invention, in particular beef and pork, to be significantly improved.

Since the method according to the invention creates an anaerobic atmosphere for the storage of meat, the lactic acid bacteria can develop optimally, whereby a taste improvement is achieved. Any risk of acidification of the meat is avoided. Oxidation by atmospheric oxygen, which would cause the formation of aldehydes and ketones, is also excluded, which could result in a rancid aroma. Since such oxidation is prevented, the fatty acids contained in the meat are not adversely affected, so that the freshness taste and the aroma of the meat stored according to the invention are fully retained.

Furthermore, the invention includes a method by which the juice holding capacity of the fresh meat is increased. It is particularly advantageous here if the individual pieces of meat are boned. In this case, such pressure is exerted from the outside that the myofibrils of the muscle fiber bundles of the meat, which are composed of thin and thick filaments, swell, so that the distances between them de between the molecules, so that more water binds between the myosin molecules. This water is immobilized, ie it is held firmly and it is no longer freely movable, so that an increase in the water binding and juice holding capacity is achieved. Furthermore, the water-binding and juice-holding capacity is increased in accordance with the invention in that the contraction of the filaments is prevented by exerting pressure on the filaments and a slow drop in temperature. As a result, the space available for the water is increased and thus the water-binding and juice-holding capacity is increased. The method according to the invention also binds the water of the sarcoplastic space, which is relatively freely movable, and the extracellular water, which accounts for less than 10% of the total water of the living muscle, in a similar manner.

Furthermore, the method according to the invention can be used to store pork used for the production of so-called chorizo - a raw sausage product based on pork. As already stated, the anaerobic atmosphere which is produced according to the invention promotes an increase in the pH value, so that the meat becomes acidic. This has a particularly favorable effect in the production of chorizo, since a slightly acidic taste which inhibits consumption often occurs here. Here, the storage period is at least 14 days.

Furthermore, the method according to the invention can be used to achieve an improvement in the quality of cooked ham, using boned pork that is brined with brine after the method according to the invention has been completed. By the invention Evening the pH value also results in a more uniform salt absorption of the meat, so that overall the shelf life, the color, the juiciness and the taste of the cooked ham are improved. Furthermore, an increase in weight of approx. 3% is brought about by the method according to the invention, so that the overall cooking losses are lower.

Overall, it can be stated that the shelf life, the color, the bacteriological load and the freshness of the meat are improved by the pH balance according to the invention, it also being noted that the texture of the stock according to the invention is also improved Meat improves because it has a short, compact and crumbly structure.

In particular in connection with poultry meat, a method is also advantageous in which freshly slaughtered poultry meat, divided into individual pieces of meat, is layered without space in a container, and then a pressure is exerted on it from the outside such that an anaerobic storage condition of the pieces of meat is exerted is reached in the container, with storage of at least two weeks at a cooling temperature of a minimum of -1 ° C and a maximum of + 1 ° C, in particular 0 ° C. This process differs from all previous knowledge for the processing of poultry, since it was previously assumed that fresh poultry cannot be stored for a long time, but rather must be consumed within a very short time.

With regard to the contamination of poultry meat in particular, the following was found: - 8th -

If freshly slaughtered poultry meat is examined with regard to the number of germs present, the number of germs is approximately 50,000 after 24 hours. After two days there is a bacterial count of approx. 150,000 to 200,000 and after four days from approx. 500,000 to 800,000.

Poultry meat stored according to the method according to the invention has a germ count of approx. 40,000 to 50,000 at the end of the storage period and this germ count increases only insignificantly even after the method according to the invention has been completed, with a shelf life of an additional one to two weeks being achieved, so that the total durability of the poultry meat is four to six weeks.

Furthermore, it is expedient here if an external pressure is generated such that an osmosis takes place within the layered pieces of meat and between them, due to the internal pressure, in order to even out the pH. Here, the method according to the invention offers the particular advantage that this meat, for example from older animals such as, for example, egg chickens, which are no longer productive, can be used, although such meat is tough when freshly slaughtered and optically unattractive because it is a has a yellowish color. Such meat is per se only reduced in price - as cooked meat or processed meat. With the aid of the method according to the invention, in particular a storage temperature of 0 ° to -1 ° C. is to be maintained, the quality and durability of the meat are now substantially improved, in particular with regard to its tenderness and color, because after a storage period of in particular three weeks, the original yellowish color is paler and thus the meat overall whiter, and in addition the structure of the meat is more compact and crumbly and therefore more tender.

Especially when using the method according to the invention in connection with the storage of poultry meat, poultry meat provided with or without skin can be used. Poultry meat that still contains bone can also be used.

In the method according to the invention, it is particularly favorable if an external pressure of at least approximately 150 kg per cm ² , in particular of 300 to 350 kg / cm ² , is exerted. The storage temperature for beef and pork is preferably 0 ° C to 1 "C and, as already stated, the storage temperature for poultry meat - l ^β C to 0 ^β C.

Furthermore, the invention relates to a device for performing the method according to the invention, as shown in the accompanying drawings and on the basis of the exemplary embodiments shown therein.

Show it:

1 is a perspective view of a container and a lid of the device according to the invention,

2 shows a perspective view of a pressurization device and 3a and 3b cross-sectional views along the line III-III of FIG. 1 of two different

Formations of the lid.

A device according to the invention for carrying out the methods according to the invention consists of a container 1 for holding meat (not shown). The container 1 is formed in the illustrated embodiment with a rectangular cross section with a bottom 2 and four side walls 3, 4, 5 and 6. Furthermore, the container 1 is open at the top. In its interior 7 delimited by the walls 3 to 6, a cover 9 can be inserted from above in the direction of the arrow 11 and can be pressed in by means of a pressure application device 12 (FIG. 2), the function of which will be explained in the following. In terms of area, the lid 9 is slightly smaller than the cross-sectional area of the container interior 7, so that there is always a gap between the lid 9 and at least one of the walls 3 to 6, through which the meat juice exiting the meat when pressurized flows and Air can escape. The pressure is exerted until the lid 9 is covered by the juice and an anaerobic storage state is thus achieved.

According to the invention, the container 1 consists of a material which has such elasticity and such a coefficient of thermal expansion that Changes in volume of the meat caused by temperature changes can be compensated for by shrinking or stretching the container 1, ie its base 2 and its walls 3, 4, 5, 6. The material used also has a low thermal conductivity. A plastic material is particularly suitable for this purpose, namely a glass fiber reinforced plastic which, in addition to the required elasticity and low thermal conductivity, also has good mechanical strength, so that even high pressures are possible without problems. Advantageously, the container 1 consists of an outer layer made of polyester resin and glass fiber mats, to which an inner cover layer made of base polyester resin, which may contain admixed color pigments, is applied. A container composition of approximately 60% polyester resin, approximately 30% glass fiber mats and approximately 10% cover layer (in each case percentages by weight) has proven to be advantageous. The container 1 according to the invention is easy to clean, hygienic and food-neutral and, moreover, also has sufficient mechanical strength to ensure the necessary pressures without cracks or other damage occurring.

Polyester resin based on orthophthalic acid polyester resin with 35% monostyrene with a viscosity of 1000 mp can be used as the base material, the 0.8 to 1% cobalt accelerator, consisting of a solution of styrene with 1% cobalt naphtenal and as a hardener 2% methyl ethyl ketone peroxide, consisting of a normally active solution of approx. 9% active oxygen, dissolved in phlegmatizing agent phthalate ester and a glycoderivative. As a reinforcement endless glass fiber mats with square meter weights of

2 450 resp. 600 gsm used. The nominal diameter of the

Elementary fiber is 15 μ. The top layer consists of isophthalic acid polyester resin with standard glycol and dispersed silica plus monostyrene and color pigments made of titanium oxide, as well as the o. a. Amounts of cobalt accelerators and hardeners.

The container 1 made from this material has a very good and long-lasting, ie non-tiring ability to expand or shrink when the temperature changes. For example, an 80 kg meat container is 620 mm high, 470 mm wide and 580 mm long at a temperature of 18 ° C. At this temperature of i8 ^Q C in the empty container 25 at height above the ground has a measured Um¬ fang of 163.5 cm. The filled, pressurized container then has a circumference of 164 cm at 15 ° C. and 163.5 cm at 3 ° C., so that sufficient pressure is guaranteed in any case even after cooling. This results from the fact that the container can be stretched so strongly elastically in the warm state by pressurization that when it cools down, this elastic pretension and subsequently, if necessary, also the temperature-related shrinkage of the container determined by the coefficient of thermal expansion of the material used for a constant or even increasing pressure inside the container. The container 1 according to the invention can be produced in any size and shape. In particular, four different standard sizes are provided, ie for 45 kg, 80 kg, 150 kg and 300 kg meat.

In accordance with the invention, the interior 7 of the container 1 extends upwards from its bottom 2. The cover 9 is preferably approximately congruent with the surface of the bottom 2. This training ensures very good ventilation of the meat. Even with small amounts of meat, the lid 9 is spaced from the container walls 3 to 6, so that the F leis chsaft and Air can escape. Furthermore, the widening shape of the interior 7 is also advantageous for the production of the container 1, since this makes it easy to remove from the mold.

To vent, d. H. To further improve the pressing out of the air from the spaces between the flesh, it is advantageous if the lid 9 on its underside 15 facing the bottom 2 of the container 1 has a preferably centrally located elevation 16 (FIG. 3a) or 17 (FIG. 3b) ) having. The elevation 16 has a trapezoidal cross section tapering away from the underside 15 of the cover 9, while in the alternative embodiment according to FIG. 3b the elevation 17 is convex. Furthermore, it is within the scope of the invention to make the entire underside 15 of the cover 9 convex. In any case, the meat is first pressed starting from the center, so that the air is pressed out laterally from the inside to the outside. The lid 9 shown in the drawing has on its top 18 facing away from the bottom 2 of the container 1 an eccentrically arranged handle 19, which facilitates removal of the lid 9, which can adhere to the meat due to adhesive forces . Furthermore, it is advantageous if the cover 9 is chamfered at its edges 21 in such a way that the underside 15 has a smaller area than the top side 18. This also contributes to the fact that air can escape well between the cover 9 and the walls 3 to 6.

In the region of its upper opening, the container 1 has an opening which surrounds the opening and extending edge 23, which is reinforced at least at two diametrically opposite points for engagement by the pressure application device 12. These reinforced points are expediently in the central region of the edges 23 of two opposite walls 3, 5 and 4, respectively.

The pressurization device 12 shown in FIG. 2 has a U-shaped bracket 25 with a web 26 and two parallel legs 27, 28. The two legs 27, 28 carry at their ends 29 mutually facing grippers 31 for gripping around the container edge 23. According to the invention, a jack 32 is fastened to the web 26, which has a lifting rod 33 which can be moved vertically in the direction of the arrow 30. At its lower end, the lifting rod 33 preferably carries a pressure plate 34 for resting on the cover 9. In the exemplary embodiment shown, the jack 32 is a mechanical embodiment, the stroke being pivoted back and forth in the direction of arrow 36 by an actuating lever 35 ¬ rod 33 can be moved vertically downwards, whereby the cover 9 is pressed into the container interior 7 via the pressure plate 34. It is advantageous if the lifting rod 33 of the jack 32 is guided through a central bore in the bracket web 26 in order to apply the compressive force in the center of the cover. The grippers fastened to the bracket legs 27, 28 are formed by angle rails, the mutually facing legs of which grip around the container edge 23. Furthermore, it is advantageous if guide rollers 37 are arranged on the legs 27, 28 with a height distance from the angle rails, which come to rest on the top of the container rim 23. The pressurization direction 12 can be pushed laterally onto the container edge 23. In an alternative embodiment of the invention, it is possible to design at least one of the bracket legs 27, 28 to be pivotable outwards, as a result of which the pressurizing device 12 can also be placed on the container 1 from above.

In summary, the design of the container 1 according to the invention offers the following advantages:

High mechanical strength combined with good elasticity, low thermal conductivity, i.e. good thermal insulation, easy to clean, hygienic, temperature and chemical resistant, contains neither dangerous nor harmful substances.

Claims

Expectations

1. A method for comparing the pH of fresh meat, in particular beef, pork, poultry, lamb and venison, freshly slaughtered meat being layered into individual pieces of meat and layered in a container without gaps, then onto the layered pieces of meat from Such a pressure is generated on the outside that, in the case of an anaerobic storage condition, an osmosis takes place within the layered meat pieces and between them due to the generated internal pressure, storage for at least seven days at a cooling temperature between -1 ° C. and approx. + 2 ° C takes place.

2. A method for storing poultry meat in the freshly slaughtered state, in which freshly slaughtered fresh poultry meat is layered into individual pieces of meat and stratified without space in a container, then such pressure is exerted from the outside that such an anaerobic storage state of the pieces of meat in the Container is reached, with a storage of about at least two weeks at a cooling temperature of a minimum of - 1 ° C and a maximum of + 1 ° C, especially 0 ° C.

3. The method according to claim 2, d a d u r c h g e k e n n z e i c h n e t that such a pressure is generated that within the layered pieces of meat and between them, an osmosis takes place due to the internal pressure generated, which causes an equalization of the pH in the meat.

4. The method according to claim 1, 2 or 3, characterized in that an external pressure of approximately at least 150 kg / cm ^{2 is} exerted, in particular from 300 kg / cm ² to 350 kg / cm ²

5. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the storage of beef and pork takes place at a storage temperature of 0 ° C to + 1 ° C.

6. The method according to any one of claims 1 to 5, so that the skin fleece surrounding the pieces of meat is at least partially removed from the pieces of meat prior to storage.

7. The method according to any one of claims 1 to 6, so that poultry meat is stored at a storage temperature of - 1 ° C to 0 ° C.

8. The method of claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that the poultry meat freshly slaughtered at the latest

Is stored 24 hours after slaughter.

9. The method according to claim 1 or 2, d a d u r c h g e k e n n z e i c h n e t that the poultry meat with and / or skin and with and / or without bones is stored.

10. The method according to any one of claims 1 to 9, d a d u r c h g e k e n n z e i c h n e t that the storage period is approximately three weeks.

11. An apparatus for performing the method according to any one of claims 1 to 10, consisting of a container with an open interior space for receiving the meat, a lid insertable from above into the container interior, the area of which is slightly smaller than the cross-sectional area of the container Interior and a pressurizing device which presses the lid into the interior of the container, characterized in that the container (1) consists of a material which has such elasticity and such a coefficient of thermal expansion that changes in the volume of the meat caused by temperature changes due to shrinkage or expansion of the meat Container are balanced.

12. The apparatus of claim 11, d a d u r c h g e k e n n z e i c h n e t that the container (1) consists of a material with low thermal conductivity.

13. The apparatus of claim 11 or 12, characterized in that the container (1) consists of a plastic, in particular of glass fiber reinforced plastic.

14. The apparatus of claim 13, so that the container (1) consists of an outer layer of polyester resin and glass fiber mats and an inner cover layer of base polyester resin, preferably with added pigments.

15. The apparatus of claim 13 or 14, so that the container (1) consists of approximately 60% polyester resin, approximately 30% glass fiber mats and approximately 10% cover layer.

16. The device according to one or more of claims 11 to 15, characterized in that the interior (7) of the container (1) from its bottom (2) extends upwards, the lid (9) preferably to the surface of the bottom (2) is approximately congruent.

17. The device according to one or more of claims 11 to 16, d a d u r c h g e k e n n z e i c h n e t that the lid (9) on its bottom (2) of the container (1) facing the underside (15) has a preferably centrally arranged elevation (16, 17).

18. The apparatus according to claim 17, characterized in that the elevation (16) has a trapezoidal cross-section tapering away from the underside (15) of the cover (9).

19. The apparatus according to claim 17, so that the elevation (17) is convex.

20. The device according to one or more of claims 11 to 19, so that the lid (9) has at least one eccentrically arranged handle (19) on its top (18) facing away from the bottom (2) of the container (1).

21. The device according to one or more of claims 11 to 20, characterized in that the container (1) in the region of its upper opening has an opening which surrounds the opening and extends outwards, which edge (23) is at least at two diametrically opposite points for tacking ¬ fen is reinforced by the pressurizing device (12).

22. The device according to one or more of claims 11 to 21, characterized in that the pressurizing device (12) has a U-shaped bracket (25) with a web (26) and two parallel legs (27, 28), the legs ( 27, 28) carry at their ends (29) mutually facing grippers (31) for gripping around the container edge (23) and on the web (26) a jack (32) is attached, which vertically into the container interior ( 7) has a movable lifting rod (33) which preferably carries at its lower end a pressure plate (34) for resting on the cover (9).

23. The device according to claim 22, so that the lifting rod (33) of the jack (32) is guided through a central bore of the bracket web (26).